docs: def get_dataframe_from_data(data):
      """
      Parameters
      ----------
      data : string or pandas dataframe.
          If string, data should be an absolute or relative path to a CSV file
          containing the long format data for this choice model. Note long format
          has one row per available alternative for each observation. If pandas
          dataframe, the dataframe should be the long format data for the choice
          model.
  
      Returns
      -------
      dataframe : pandas dataframe of the long format data for the choice model.
      """
      if isinstance(data, str):
          if data.endswith(".csv"):
              dataframe = pd.read_csv(data)
          else:
              msg_1 = "data = {} is of unknown file type."
              msg_2 = " Please pass path to csv."
              raise ValueError(msg_1.format(data) + msg_2)
      elif isinstance(data, pd.DataFrame):
          dataframe = data
      else:
          msg_1 = "type(data) = {} is an invalid type."
          msg_2 = " Please pass pandas dataframe or path to csv."
          raise TypeError(msg_1.format(type(data)) + msg_2)
  
      return dataframe